Switching system of electrical signal



y 3, 1960 SABURO MUROGA 2,935,737

swncamc SYSTEM OF ELECTRICAL SIGNAL Filed Aug. 28, 1956 4 Sheets-Sheet 1y 1960 SABURO MUROGA 2,935,737

swmcnma SYSTEM OF ELECTRICAL SIGNAL Filed Aug. 28, 1956 4 Sheets-Sheet 2May 3, 1960 SABURO MUROGA SWITCHING SYSTEM OF ELECTRICAL SIGNAL Fi ledAug. 28, 1956 4 Sheets-Sheet 3 y 1960 sABuRo MUROGA 2,935,737

SWITCHING SYSTEM OF ELECTRICAL SIGNAL Filed Aug. 28, 1956 4 Sheets-Sheet4 provided. that a, b, c,

United States Patent SWITCHING SYSTEM OF ELECTRICAL SIGNAL SaburoMuroga, Tokyo, Japan, assignor to Nippon Telegraph and Telephone PublicCorporation, Tokyo, Japan, a corporation of Japan Application August 28,1956, SerialNo. 606,655

4 Claims. (Cl. 340---174) This invention relates to magnetic switchingdevices and more particularly to magnetic switching system.

In the various equipments which comprises logical circuits, as forexample electronic computer and telephone electronic exchange equipment,the switching device is one of the fundamental circuits, and isindispensable. And'especially in the case of electronic computers andthe like, to which a parametric excited resonator that is to sayparametron is applied, a simple switching device without using vacuumtubes or parametric excited resonators has been in great demand. It is aprincipal object of the invention to provide a magnetic switching systemand the magnetic device, withwhich such a need is filled.

It is a primary object of this invention to provide a magnetic switchingdevice having a simple construction, requiring only the placing of a fewpieces of winding on a few small sized magnetic cores to construct aswitching circuit.

A further object of this invention is to provide a switching systemwhich can be very stably operated for a time extending over anexceedingly long period.

The invention has for its object, a switching device withoutaccompanying significant time lag such as a mechanical relay or aparametric excited resonator necessitates, resulting in a switchingdevice usable for an electronic computer or electronic exchangeequipment for a telephone system or other various equipments requiringswitching devices.

This invention provides a switching device which possesses excellentcharacteristics for use'in-various logical operation circuits usingbinary phase signals.

In order that it may be clearly understood andmore readily carried intoeffect, the invention will now be described, by way of example, withreference to the accompanying drawings, in which:

Figs. 1 and 2 are schematic diagrams of two examples of the circuitaccording to this invention.

Figs. 3, 4, 5, 6 and 7 are respectively circuit diagrams in cases wherethe devices of this invention are applied concretely; and Figs. 8a and8b are block diagrams showing by way of example cases where the devicesof this invention are applied to the circuits of parametric excitedresonators.

The invention is constructed by winding primary windings and secondarywindings on a magnetic core, and applying an electric current I to theprimary winding so that the voltage V that is induced in the secondarywinding, if non-linear type characteristic of. the magnetic core istaken into account, then, becomes V=aI+b1 +c1 (1) are complex numbers.But

for approximate treatment, if terms of. degrees higher than the thirdare ignored it is expressed thus,

. in the same direction.

2,935,737 Patented May 3, 1960 ICC Usually, a has an imaginarynumberlarger than its'real number and bhas a real number larger than itsimaginary number.

Now, as shown in Fig. 1, for example, an input coil 11 and an outputcoil 14 are wound in series to three ferrite toroidal cores 1, 2' and 3and control coils 12 and 13 are Wound in series to the cores 1 and 2, sothat in each. of these magnetic cores the number of windings in an inputcoil 11 and an output coil 14 are the same, and the polarities ofinputand output windings are made On the magnetic-core 3, asshown in Fig. l,the input coil 11 is wound with the same numberof turns on the cores 1or 2, and the output coil'14 is wound. with double the number as thecores 1 or 2. And the polarity'of'the' output coil is opposite to thatof the input. coil. Moreover, thecontrol windings 12 and 13 are woundin. same direction, and, referring to the magnetic cores 1 and 2, assumethem to take opposite directions against the input and output windings.Now if, the electric current that flows in the input coil llis I and theelectric currents that flow. in the control coils 12, 13- is I and 1respectively, then the voltage V, that is induced in the end of theoutput coil at the magnetic core 1 is given as follows from the 2ndequa- Similarly, if the voltages that are induced in the output windingsin the magnet-cores 2 and 3 are denoted as V and V3, respectivelyfollowingequations are obtained.

Consequently, the voltage V that appears at theoutput winding 14. isgiven as follows:

Therefore, in case of 1 -I3 V =O (7) Andsuppose :1 then, next equationis gained.

V =24bI I (a) That is, it is possible to obtainonly an output voltagewhich isproportional to the input signal current 1,, by a selection ofthe frequency of the control current 1 beyond the frequency range of thesignal current I or as a direct: current; In a. case where the controlcurrent has the same frequencywith the input signal, provision of'aWavefilter will cause the same effect. Further, as mentioned above, twocurrents with the same arbitrary frequencyand with the same arbitrarywaveform may be appliedto the control windings. in parallel. If the twocurrentshave the same phase, the input and output coils 11 and-'14 arecoupled and if they have the opposite phase, coupling between two coilsis out OK. It is needless to say that, in this case the optionalfrequency and waveform are applicable to the input signal current andcontrol current.

Further, as mentioned above, if the two windings of the control coilwhich are in parallel, have currents of equal optional frequency andoptional waveform and in' the same phase, applied thereto then the inputand output coils 11 and,14 are coupled. If control'currents of oppositephase are applied then coupling iscut ofi. Therefore we can constructthe switching device quite simply and easily. But, it is also possibleto control the couplingbetween, input. and output. coils by means ofmaking or breaking of their control current, byusing only one set ofwindings for the control coil in the cores 1 and 2.

As mentioned above, the device of this invention has the appropriateinput winding, output winding and con trol winding on the three magneticcores, and in case no magnetic field, due to the control winding, isapplied the components which are proportional to the input current inthe output voltage induced on the output coil coupled with variousmagnetic cores cancel each other, and in case where alternate magneticfield due to the control coil is generated, there arises an outputvoltage which is proportional to the input current by the non linearcharacteristic of the magnetic cores or a small output voltageproportional to the odd powers of the input current. That is, in theexample shown in Fig. 1, only an output voltage which is proportional tothe input current of coil 11 is produced in case when the magnetic fieldwas given by the current of control coil as shown in the Equation 8.But, for instance, as shown in Fig. 2, the magnetic cores 1 and 2 arethe same as in Fig. l, and the polarities of the input coil and outputcoil of the magnetic core 3 are also the same as in Fig. 1, but thewinding number of input is double to those of cores 1 and 2 and outputwinding is wound with the same number as the magnetic cores 1 and 2.Therefore, if the current I of the control coil 12 and the current I of13 have the relation I -I the output voltage V to the input winding 1 isgiven as,

V,,=6bl (9) and in case of I =I becomes as,

V,,=24bI I --6bI (10) and a component that is in proportion to the cubeof the input signal current 1 is contained in the output voltage. Forthe same usage, however, the output voltage corresponding to this term6I2I gives no trouble and control coils 12 and 13, even though thesignal current flows in the output coil, no voltage is induced in theinput coil, so that the back coupling from the output coil to the inputwindings can be cut off completely.

Fig. 3 shows an example in a case wherein the said device of thisinvention is employed, and in which one of the two input signals iscoupled to the output circuit. That is, the switching device whichconsists of the magnetic cores 1, 2 and 3 has entirely the same circuitas in Fig. 1 and the control coils 12, 13 of the switching device whichinclude the magnetic cores 1', 2' and 3' is wound in reverse directionto each other at the magnetic cores 1 and 2. Besides, on the cores 1'and 2', the control coils 12 and 13 are wound in reverse direction, inrelation to the input and output windings 11 and 14. And the output coil14 and the control coils 12 and 13 connect in series with two sets ofthe switching device which comprise the magnetic cores 1, 2 and 1 3, and1', 2', and 3'. Therefore, if the control alternating currents of thesame phase are applied to the terminals of the control coil terminals Tand T the signal source e is coupled to the output coil 14 through themagnetic cores 1, 2 and 3. And if the control alternating currents haveopposite phases, the signal source e is coupled to the output winding 14through the magnetic cores 1', 2' and 3'. Therefore, either signal oftwo signal sources e and 2 can be selectively taken out at the outputcoil terminal OP.

The embodiment of Fig. 4 has the same function and almost the sameconstruction as that in Fig. 3, except a common magnetic core 3"performs the roles of magnetic cores 3 and 3' in Fig. 3.

Thus if the relation I =I holds, the output voltage V to the inputsignal currents I and I of the signal sources e and e is as follows:

V =24bI l -6b(111 1 1 11 (11) And in case where I =I it becomes,

Y out-of-phase then:

But the second terms of these Equations 11 and 12 are small and can beneglected. Moreover, it is possible that when the output terminal isnewly considered as the input terminal, single input signal can becoupled to either of two output terminals, because the circuits of Fig.3 and Fig. 4 are reversible.

Further, if we want to select one out of many input terminals which isto be coupled to one common output terminal, all input sources e, e, e",are coupled to switching devices of the same number with the inputsources and each of the switching devices comprises three magnetic coresas 1, 2, 3; 1', 2, 3; 1", 2", 3", as shown in Fig. 5. The controlwindings are also arranged as 15, 16 and 17 and the like. Andcorresponding to the signal applied at the control terminals T and T thecontrol currents are given to them, after proper combination in thecircuit C. That is, for example, by means of the multi-hybrid circuit, acontrol magnetic field is induced only in selected one out of N sets ofmagnetic cores 1, 2; 1', 2'; 1", 2"; and cancelled or small enough inthe remaining (N-l) sets of magnetic cores. Therefore only one signalcan be coupled to the output coil 14.

And the magnetic cores 3, 3', 3 bined properly as in the case of Fig. 4.

The practical applications of the switching device of this inventionwill be stated as follows. The example shown in Fig. 2, it was statedthat the output voltage concerning the polarity between the electriccurrents I and I of the control coils 12 and 13 was given by theEquations 9 and 10. If it is assumed that the input signal current Icontrol current I and I have the same frequency, and are sine waves andare either in phase or [1 141 Sin wt lz=il3=tA3 Sin wt That is, assume Ihas a value of either +1 or I;,, the Equations 9 and 10 become for . canbe com- 2=- a V =6bA sin wt =4.5bA sin wt+1.5l7A sin wt (15) and for 1313 V =18bA A sin wt6IJA A sin wt --4.5bA sin wt+1.5bA sin wt =4.5bA1(4A3A1 Sill wt --1.5bA (4A A sin wt (16) Therefore, if the third harmonicwave is removed by a filter, as for example, a resonance circuit, theoutput voltage is V =--4.5bA sin wt (17) V =4.5bA (4A -A sin wt (18) Asit is clearly known from the said Equations 17 and 18, that when it isassumed |2A A in the circuit shown in Fig. (2), the outputs phase isshifted so that differs by degrees. And assuming the phase of the signalcurrent 1 for example, as O radian, and if the phases of I and I areboth either of 0 or 1r radian, then the phase of the output voltagebecomes 0 as shown by the Equation 18. If only either of them is 1r or 0radian and the other is an opposite phase, the phase of the outputvoltage becomes 1r as given by the Equation 17. And if the phase of I is1r, when the phases of 1 and i are both either 0 or 11', the outputvoltage becomes 11' phase. And, on the contrary, when either one of themis O or 1r and the other is its opposite phase, the phase of the outputvoltage becomes 0. Therefore, in the control device of Fig. 2, assumingthat the input signal current 1 and the control coil currents 1 are sinewaves of the same frequency, and that these currents are considered tobe the asaam it is possible to make the amplitude of the output voltagesgiven by the Equations 17 and 18 equal at any time. And the number ofturns of the input windings on the magnetic cores 1, 2 and 3 are notnecessarily limited to be 1 to 1 to 2. If the polarity of the outputvoltage which is same as I shifts corresponding to cases where I and Iare inphaseor out-of-phase.

If in the circuit of Fig. 3, the terminal T of the control coil 12 isconnected with the signal source 2 and the input sginal current I, ofthe control coils 12 on the cores 1, 2 and 3 is in phase with the inputcurrent, and currents I and I that flow in the input coils 11, 11" and.

the current I that flows in the control coil 13 are sine waveswhich-have the same frequency and are in-phase or out-of-phase, forexample, then as the phase of 1 and the phase of 1 are always the same,and if'I and I have opposite phases, the. output voltage in the outputcoil has a phase corresponding to the phase of current 1 of the inputcoil 11'. And if I; and 1 are in-phase, the phase of the output voltagecorresponds to the phase of I That is, when I is always kept at radian,if I and I have opposite phases to each other or both have 0 radian, theoutput will have 0 radian. And when I is always kept at 7r radian, ifany only if both I and I have 0 radian. Therefore, if I and 1 arerepresentative of two logical variables of binary phase signals, thiscircuit has the function of a logical addition circuit or logicalmultiplication circuit. Moreover, by shifting the phase of I conversionbetween an OR circuit and AND circuit can be carried out quite easily.It is characterized by the fact that the output amplitude always isstable. And in the said Fig. 3, it is quite easy to operate the circuitshown in Fig. 6 and Fig. 7 by proper phase shifting to couple theterminal T with the signal source e. And, further, the cores 3 and 3'can be combined together into one core. That is, these circuits can bealso operated as the OR circuit or AND circuit for the binary phasesignal of the signal sources e and e.

As mentioned above, the switching device of this invention is applicableto the various logical circuits for binary phase signals. And as known,and clearly described in applicants patent application Serial No. 508,-

. 668 filed on May 16,1955, in a parametron when a resonant circuitincludes at least one non-linear element is excited by a signal Whosefrequency is double the resonance frequency, an oscillation which hasthe resonance frequency is induced in the'output circuit; and the phaseof the output oscillation is controlled so that it is 0 or 11', by thephase of the control signal which is impressed on the resonant circuit,The parametrically excited resonator parametron, such as mentionedabove, is used for a digital computer or the other logical circuits.Therefore, when the switching device of this invention is used as a partof such a computer or in the other heretofore mentioned systems aneconomy of power, and minimization of equipments and a decrease ofoperating hours can be carried out. For example, in Fig. 8 (abusing themodulo 2 adder A explained in Fig. 2, impress signal of 0 radian whichindicate 0 of binary number as one input of it, and the outputs ofparametrons P and P as the other input. And then impress the output ofmodulo 2 adder A is to parametrons P and P in regular succession. Andthe output of parametron P is fedback to the parametron P And ifparametrons P P P and P are excited in known manner at the successiveexcitation periods I, II and III, as long as parametron P delivers thesignal which in aieatesfo a einar number, tae same signal is' held -in,

a'loop of modulo 2 adder 'A and the parametron P5 1, and P and hold it.But, corresponding to 'the signal of the input terminal IP, ifparametron P delivers at the signal which'indicates l, thatis, 1rradian, the modulo 2 adder A adds it modulo -2 tothe held signal andhereafter, the signal bearing the value is held Therefore, this circuithas the function of a flip-flop circuit and can take out the output fromthe output terminal OP, or from other parametron in this loop. And whenmodulo 2 adder A in the same figure is replaced with the switchingdevice for two input signals such as shown in the i Fig. 3, by thecontrol signal given from the terminal G shown by the dotted line, thesignal of parametrons P or P can be delivered optionally to theparametron P So parametrons P P and P can function as a register to thesignal of parametron P Furthermore if the parametron P is removed fromthe circuit of Fig. 8 (a) and a directional coupler D is inserted asshown in Fig. 8' (b). the parametrons P P and P can be excited at thealternate excitation periods I and H to have the same operation asmentioned above. The

' device by means of this invention, as shown above, with parametrons,can have various functions and it contains the higher harmonics, overthe third harmonic. Therefore, if such means as rid the arrangement ofundesirable harmonicsby using a resonance circuit, as occasion demandsor to carry out the adjustment of the value or" voltage and 1 electriccurrent by means of the resistance potential divider are used, variousequipments which have other complex'functions with the slightest timelag can be, obtained. It will lac-understood that in this invention,needless to say, a bias magnetic field can be added by. direct current,according to circumstances, in order to adjust the characteristic of themagnetic cores. What I claimis: 7

l. A switching device comprising, an odd-number ofnon-linear magneticcore elements, an input coil having turns wound serially on said coreelements, an output coil having turns wound on said core elements, meansfor applying an input alternating current signal to said input coil,means for coupling and uncoupling the input and output coils comprisingmeans for generating unbalanced magnetic fields in said core elements toinduce an output signal in said output coil corresponding to theinputsignal comprising parallel control coils having turns wound serially onan even number of said magnetic cores in opposition to the input andoutput turns, and means for applying control currents of equalfrequencies and the same phase to the control coils to induce saidoutput signal.

2. A switching device according to claim 1, in which said cores areFerrite torrodial cores.

trol coils having turns formed on two only of each of the sets of threecores, means to apply to the'control coils control alternating currentsof equal frequencies and alternatively of the same phase and oppositephases.

4. A switching device comprising, two sets of magnetic non-linearelements, each set comprising three core elements, one of said coresbeing common to both sets, for each set of three core elements an inputcoil having turns wound serially on saidcore elements, an output coilhaving turns wound on said common one of the cores of each setof coreelements, means for applying a respective input alternating current tothe input coils, means for References Cited in the file of this patentUNITED STATES PATENTS 2,666,151 Rajchman et al Jan. 12, 1954 2,696,347Lo Dec. 7, 1954 2,729,807 Paivinen Jan. 3, 1956 2,846,671 Yetter Aug. 5,1958

